Data loggers for recording telephone calls received over one or more incoming telephone lines are known in the art. Data logging systems exist to record voice telephone calls and fax transmissions. An example of a prior art data logging system, generally referenced 20, is illustrated in FIG. 1. The system 20 is utilizes a local area network (LAN) 28 for communications between loggers 24 and a controller 26. Each logger 24 is responsible for recording communications on a plurality of input telephone lines. In order to provide backup logging capabilities in the event a logger fails, spare loggers 22 are provided. Each logger 24 has associated with it a spare logger 22 that is kept ready for use in the event its associated main logger 24 fails. In order to provide logging service in the event logger 24 fails, each spare logger 22 is also coupled to both the plurality of input telephone lines and the LAN 28. When a logger fails, its spare takes over and continues to log calls.
A disadvantage of this prior art logging system is that it is very wasteful of hardware resources. Redundancy is achieved at the high cost of providing a spare logger for each logger. Using this prior art redundancy scheme, every system that is to have failure protection is encumbered with 100% redundancy overhead which almost doubles the cost of each system. On large systems this is very inefficient and very costly to implement since for the majority of the time the spare loggers are not in use.